Study BMB 464 Exam 1 Viruses Flash Cards

 
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BMB 464 Exam 1 Viruses

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HA vs. N antigens
HA= highly virulent
N= not as virulent, less immunogenicity
Salk vs. Sabin vaccines
SALK:
-2 intramuscular shots
-booster every 5 years
-safe

SABIN
-oral dose
-booster beginning of school year
-not in US
-no longer recommended
Bruce Savin (1957)
-developed oral polio vaccine
polio vaccine
-Salk (1947)
-grew virus in monkey renal cells
-3 strains inactivated w/ formulin
-1987--> new version grown in human cells --> higher antigenicity
-Bruce Savin developed oral vaccine in 1957
polio
-enters nose and mouth--> intestines--> bloodstream--> AB production clears virus--> lifetime immunity
-1% paralyzed (brain--> SC--> limbs or lungs)
-highly contagious
vaccine problems
-weak immunity
-side effects
-may cause autism
-may cause disease
how vaccines are made
-viruses killed
-live attenuated (less strong)
-virus proteins: capsid proteins, recombinant vaccines combine viruses
passive immunity
-ABs given directly
-ex: rabies
-mother-to-child
-immediate protection
-short-lived
active immunity
-exposure to entigen
-triggers immune response
-produces ABs
-long-lasting
-takes time to develop
1st vaccine
Edward Jenner for small pox
global pandemic occurs if...
1. new strain
2. virus causes serious illness
3. spreads easily from person to person
antigenic shift
-2 different strains of a virus combine to form a new subtype
-has mixture of the surface antigens of the two original strains
-jumps from one animal to another
-infrequent, sudden, more dramatic changes
antigenic drift
-natural mutation over time of known strains of influenza
-Random mutations in the genes of a virus
-changes the antigens of the virus.
-help the virus to evade the immune system if antigens change
-results in loss of immunity or vaccine mismatch
why are pigs "viral casseroles"?
pig cells contain receptors to permit infection by different strains (avian, swine, human)
flu evolution
-influenza A isolated from many host species
-lived in aquatic birds for millions of years
-increased mutation enabled virus to jump from wild birds--> domesticated ducks--> chickens--> pigs
-pig cells contain receptors to permit infection by different strains (avian, swine, human)
viruses enter host cells via...
...receptor-mediated endocytosis
steps of viral life cycle
1. adsorption
2. entry
3. replication
4. viral gene expression
5. production of virion components
6. virion assembly
7. release
how to evade host cell's immune responses
-enter latent state (hidden from ABs)
-vary antigenic surface proteins
-block production of immune complexes
-cytolysis of immune cells
-reduce antigenic presence by B cells
-inhibition of inflammation
viral pathogenicity
-depends on:
envelope, capsid proteins, nucleic acids, viral protein production, cell's permissiveness
-evading host cells' immune responses
influenza B
-only in humans
-mutates 2-3x slower
influenza A
-most virulent, most common
influenza basic info
-upper resp tract
-surface proteins: Hemagglutinin (HA) and Neuraminidase (N)
-influenza A vs. B
-8 segmented (-) ssRNA, each encodes for a separate viral protein
persistent infectious cycle
-virus is not cleared but remains in specific cells of infected individuals.
-may involve stages of both silent and productive infection
-no rapid killing or excessive damage
-3 types of overlapping persistent virus-host interaction: productive, latent, transforming
abortive infectious cycle
-after initial infection the viral genome is lost from the host cell or from successive generations
-only temporary malignancy
+ RNA
-in same reading frame as mRNA
-particular viral RNA sequence may be directly translated by the host cell
-can be considered "viral mRNA"
virus classification based on...
1. basic structure
-isohedral (20-sided)
-helical

2. nucleic acid
-ds or ss
-RNA or DNA
- (+/-) RNA

3. infectious cycles
-abortive
-lytic
-persistent- productive, latent, and transforming (tumor viruses)
emerging disease
-appeared in a pop for the 1st time, or may have existed previously, but is rapidly increasing in incidents or geo range
-ex: flu, polio
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